Wolfram Alpha: How to evaluate the difference of a function at two points

Question

I'm just using the website and not the programming language or anything like that. I want to type in:

evaluate x from 2 to 5

and get 3 back as an answer, but instead it's drawing a graph and then giving me the arc length of the curve between those points. I've also tried

f(x)=x; f(5)-f(2)

but that doesn't seem to work either. Is there any built-in way to do this? Asking because it's a real pain to copy-and-paste and substitute 2 for 5 for more complicated functions that use x multiple times.

Answer 1

Have you tried something like

f(y)-f(x) substitute (x,y) = (2,5)

or for more complicated expressions

f(y)-f(x) /. {x=2,y=5}